A valve controller is disclosed for reciprocating piston internal combustion engines with at least two intake and/or exhaust gas-exchange valves for each piston/cylinder unit, wherein these gas-exchange valves are guided by valve stems in a cylinder head of the reciprocating piston internal combustion engine and are loaded in the closing direction by valve springs and can be controlled via a common bridge through the use of an activation device.
A class-defining valve controller of this type is known from U.S. Pat. No. 6,883,492 B2. This valve controller has a bridge that is guided over both valve stem ends in such a way that recesses are provided in the bridge, wherein the valve stem ends project into these recesses. The bridge is controlled by a master piston of a hydraulic activation unit, wherein the master piston includes a hydraulic valve clearance compensation element. This hydraulic valve clearance compensation element is in no way sufficient to guarantee equal movement of the gas-exchange valves both in the closed position and also in the open position, because the valves are guided more or less rigidly by the bridge and recesses in the bridge that enclose the valve stems (see FIG. 2). A risk, in particular, is that the gas-exchange valves will not close cleanly at the same time.
Furthermore, a valve controller for reciprocating piston internal combustion engines is known from US 2006/0432 A1, that also has a bridge containing recesses for the valve stems and furthermore a sliding surface that encloses a guide rod attached to the cylinder head. This patent application explicitly involves a closing body that is inserted into the bridge and that is in active connection with a valve lifter of an activation device. This valve lifter is driven conventionally via a tappet push rod and a cam follower by a cam of a camshaft. This activation of the gas-exchange valves is also not satisfied when the bridge is guided, because the gas-exchange valves are forcibly guided, so that there is also the risk that they do not close exactly and equally.